Type Forming

I'm looking for a book or paper that gives a good description of type forming, preferably something by a naval architect. Googling turns up a lot of references to IOR rules, but nothing devoted to the process itself.

I'm hoping to find something I can reference in place of an essay of my own that circumstances are precluding me finding time to write.

Cheers,

Earl

 

The only type forming I know of is for working sheet metal. Is that what you are looking for?

 

Er, no. I was referring to the process whereby a set of class rules (usually a box rule) favors a particular design either by accident or intent, and designs converge onto that particular type. When the process ends the class becomes de facto one design.

Cheers,

Earl

 

Most class rules are beaten not by good design, but by a legalistic approach. Often, like when Dennis Connors raced a catamaran against a monohull, the race was won in court by lawyers. Therefore, you are better off asking lawyers than designers.

 

Oh, sure, but I'm interested in the technical process whereby designers find a unique "sweet spot" in the legal design space and the evolution of the class stops.

Cheers,

Earl

 

Designers don't find the sweet spot, owners do. Take a look at this post from some time ago. It sums up all the major points.

http://www.boatdesign.net/forums/sailboats/americas-cup-whats-next-31489-5.html#post364487

 

Perfect. Exactly what I was looking for. Many thanks.

Cheers,

Earl

 

Type forming is just a somewhat pejorative term for evolution. Evolution towards an optimum design. Its born out of the myth that its possible for rule makers to construct a rating rule that has no perceived optimum. The reason why it happens with racing craft is that the "fittest" - as we are talking about evolution lets say that - is fairly easy to measure because there's one metric: race results.

There's always been a desire in the "boats with lids" racing community that a rating rule should have two quite incompatible aims: one that the best crew should win, regardless of what boat they are in, and the other that better design should be rewarded. That's better in terms of the "fitness" metric of racing success of course. Those who don't like the kind of boat that's optimum complain the rule is type forming.

The contrast, of course, is with non-racing craft where there is no obvious simple metric of success, and as a result all sorts of weird stuff can flourish, since the only real metric of success is "does the owner like it".

 

Another thing to consider is in handicap racing, the goal is not necessarily to build a faster boat. Races are won with boats that are not quite as slow as their rating would indicate.

 

The other thing is that "box rules" are just as typeforming as measurement rules in many ways. The design of an Open 60 or 12 Foot Skiff is just as driven by their class rules as IOR boats were driven by that rule.

 

In PHRF, you can consistently win with a good crew. Get a boat that rates low in the area because it was sailed badly and win a season. Resell at a profit, because people like to buy winning boats, and buy a different design that was sailed badly.

 

If not more so. But I think its fair to say that in general its not regarded as a problem in the same way. I don't know of a box rule class where there's pressure to attempt to make very differently shaped boats race evenly together.

 

No, box rules end up with boats that are very similar. Sometimes, like with foils, there is a radical change. However, in short time, they all end up very similar again.

 

Any development class if allowed to progress long enough will eventually settle on an 'optimal' solution within the design rules. Once that optimal solution has been developed small incremental progressions are all that will be achieved.

Right up to the point someone makes a major breakthrough and it happens all over again.

The Moth had almost no development for years until it started to foil, then inside just a couple every boat was a foiler, or not racing anymore

The A-Cats are going thru it now, but the development track is a little slower.

TP-52's came out of the gate at pretty much their optimal design and haven't changed much since. In large part because the box rule is so tight.

 

"Type Forming" is used as a derogatory term for design rules which favor one particular solution over other others that are class legal. For example, the AC keel boat class favored narrow heavy designs over light wide designs.
However, type forming is inevitable if one is intending to organize sailing classes. Simply states, the boats have to be similar enough to provide satisfactory competition. In this explanation, you can see that there is a continuum from the loosest rule " Boats are 18 feet long. Race starts at 2" to the Single manufacturer One Design where anything not provided by the manufacturer is not allowed.
Every other development class rule has some aspects that type forms. A class catamarans have to be catamarans. Moths have to be 11' mono hulls with only one sail. International Canoes are pointed at both ends and have a sliding seat etc.
So while type forming is decried by those who don't think their pet idea is being arbitrarily excluded, one has to accept that every class has to be type formed to some extent simply to be identifiable as a class.
SHC